An information processing system such as a parallel computer system includes a plurality of information processing devices which are connected through a lane which is a data transmission path. For example, an information processing device using Ethernet (registered trademark) of 100 Gbps, which is defined in IEEE802.3ba standard, transmits data to an information processing device of a communication destination through a link including a plurality of lanes. Hereinafter, Ethernet of 100 Gbps is referred to as 100 Gb Ethernet. In the standard specification of 100 Gb Ethernet, an alignment marker is inserted between data blocks for each lane in order to detect skew between data lanes and detect data errors.
The physical layer of the IEEE802.3ba standard does not have a function of specifying a failed lane and a function of causing a lane to be degenerated. Therefore, if one lane among a plurality of lanes is failed, the link is disconnected and thus the reliability of the parallel computer system is reduced.
A so-called lane degeneration method (also known as degradation method) has been proposed in which a failed lane is disabled and data is transmitted using a lane operating normally in order to suppress the deterioration of the reliability of the parallel computer system (for example, see Akihiro Kanbe, Masashi Kono, and Hidehiro Toyoda, “Lane Degeneration Technology for 100 Gbit Ethernet”, IEICE Technical Report CS2010-39, pp. 13-18, November 2010). For example, lane degeneration is realized by inserting a switching control marker for controlling the switching of a lane at a position different from the position of the alignment marker between data blocks.
Further, a method has been proposed which suppresses power consumption by changing the number of lanes for transferring data based on the number of requests per unit time, in a data transfer system that transfers data using a plurality of lanes (for example, see Japanese Laid-open Patent Publication No. 2011-123798).
However, in the technology of inserting a switching control marker at a position different from the position of the alignment marker, it is difficult to adopt this technology in the physical layer protocol conforming to IEEE802.3ba standards. Therefore, in this type of system, the physical layer protocol is changed, and a circuit block for realizing a physical layer is newly designed according to the modified protocol.
In an aspect, an object is to provide an information processing device, an information processing system, and a communication device that detect a failure in a lane and cause the failed lane to be degenerated, even when an interface unit that inputs and outputs data to a lane is an interface unit in which a degeneration control function is not defined in a protocol or a data format.